It is known to pack hygroscopic or deliquescent materials in granule or powder form, for example coffee, in cups intended for use in machines for dispensing liquids. Such materials are dissolved in water to form the liquid being dispensed, and, on storage prior to the addition of the liquid, tend to attract and absorb moisture. Accordingly, it is desirable to protect stacks of cups intended for use in dispensing machines of the type described from exposure to moisture during storage. United Kingdom Pat. No. 1,062,436 describes and claims a package of nested cups for use in a dispensing machine, each cup containing a measured quantity of dehydrated material, for example instant coffee powder, wherein the desired protection comprises a bag of moisture impervious material enclosing the stack of cups and shrunken into engagement radially with said cups and axially against the ends of the said stack.
In the package disclosed in U.S. Pat. No. 1,062,436 the bag is made of a plastics material of the type which shrinks when subjected to heat and retains its shrunken condition when the heat is removed. An example of a suitable plastics material is transparent plastic film sold under the registered trade mark "Cryovac". The bag used to produce the said package is a hollow tube of plastics material closed at one end having its other end open to receive the stack of nested cups and subsequently sealed by twisting the material and holding it with a clamping device after the stack is inserted. After sealing, the bag is shrunken by immersion in hot water, thus providing an endwise pressure which maintains the cups in an interlocking position and provides a useful seal. Although the package described in U.S. Pat. No. 1,062,436 is a vast improvement over previous packages, the shrinking does result in moisture remaining in the twisted film above the metallic sealing clip referred to. Micro-leakage of this moisture, for example by capillary action, into the package can occur through the clip seal. This reduces the storage life of the powder. There is also a certain amount of wastage of plastics material resulting from the twisting and clamping of the material to seal one stack in that up to one quarter of the initial bag length is required to be cut-off and discarded. A further disadvantage of the shrinking process is that some distortion of the cups can occur, thus making automatic cup dispensing difficult.
It has been found that these disadvantages may be avoided and a sealed package having an improved storage life for the beverage ingredients contained therein may be provided by forming a wrapping as hereinafter described.
The present invention provides an alternative process to that described in U.S. Pat. No. 1,062,436 and is a vertical form, load and seal technique using flexible packaging films or film laminates. It gives packages having an improved shelf-life over packs described in U.S. Pat. No. 1,062,436 when appropriate materials are selected, together with a saving in material and labour costs and an improved print design is available, and does not involve the use of vacuum packaging.